Modern communication and data networks comprise network nodes, such as routers, switches, bridges, and other devices that transport data through the network. Over the years, the telecommunication industry has made significant improvements to the network nodes to support an increasing number of protocols and specifications standardized by the Internet Engineering Task Force (IETF). Creating and coupling the complex network nodes to form networks that support and implement the various IETF standards (e.g. virtual private networks requirements) has inadvertently cause modern networks to become labyrinth-like and difficult to manage. As a result, vendors and third party operators struggled to continually customize, optimize, and improve the performance of the interwoven web of network nodes.
Software defined networking (SDN) is an emerging network technology that addresses customization and optimization concerns within the convoluted networks. SDN simplifies modern networks by decoupling the data forwarding capability (i.e. the data plane) from routing, resource, and other management functionality (i.e. the control plane) previously performed in the distributed network nodes. To streamline the control plane architecture, SDN implements a logically centralized system, which may include one or more centralized controllers, to manage the control plane. For example, software in multiple servers that are separate from the network switching nodes may manage a network's control plane functions, while the network switching nodes within the network are configured to govern the data plane. Currently, the OpenFlow protocol was created to support SDN in the industry, and provides communication between the data plane and the control plane. The OpenFlow protocol enables operators or other third parties to separate the control plane configurations and the data plane configurations for a variety of network switching nodes. Therefore, the adoption of the Open Flow protocol with SDN enables vendors and third parties to easily create new network management and control applications that optimize and increase network performance.
Although the combination of SDN and the OpenFlow enables network customization and optimization, the designation of a centralized system to manage all control plane functions inherently produces drawbacks for a network. For instance, an SDN/OpenFlow network is more susceptible to failures within the centralized systems which may cause computing and processing bottlenecks. Furthermore, a centralized system may lack the dynamic ability to easily adapt and manage varying traffic volume across different network locations. Network scalability also becomes a concern when costly upgrades are necessary for the centralize system to manage newly provisioned network nodes and end services (e.g. hosts).
To alleviate these concerns, one design option has been to use a distributed control system that utilizes a cluster of central controllers. The cluster of central controllers may function as a logically centralize system without being physically centralized. However, use of distributed control systems encounter load balancing and path rerouting issues caused by centralized controller failures (e.g. single-point-of-failures). Dedicated and inflexible control channels between every controller and all network nodes may be necessary to implement the control plane. Furthermore, as the number of centralized controllers increase, synchronization and other process delays between the centralized controllers and the network nodes may affect the managing capacity of the logically centralized system. Thus, new technology is necessary to address the problems of implementing SDN and OpenFlow in large intricate networks.